Whole Foods announced the discovery of the hack in a press release issued Thursday afternoon. The release revealed payment card information at certain venues (e.g. taprooms and full table-service restaurants located within some Whole Foods stores) was accessed without being authorized.

Both the primary checkout system of Whole Foods Market stores, as well as the systems of parent company Amazon, were said to have been unaffected. The grocer has contacted law enforcement and is conducting its own investigation.

Not divulged were details of how many customers were affected, when the first instance took place, or when exactly the company became aware.

Whole Foods told Benzinga late Thursday that it did not wish to comment on the breach beyond what was included in its announcement.